The invention relates to a motor-compressor, particularly for refrigerating machines of small dimensions.
Motor-compressors for refrigerating machines, such as domestic refrigerators, freezers and air-conditioning appliances, are known in many different constructions. They serve to compress the gaseous refrigerating agent introduced into a housing of the motor-compressor. The compressor forms, conjointly with an electric motor, a preassembled subassembly which is suspended or braced resiliently in the gas-tight and pressure-tight housing. Known electric motors having a hollow cylindrical stator and a cylindrical rotor are normally used, and the rotor shaft is generally arranged offset at 90.degree. to the compressor piston and drives the piston via a connecting-rod. In order to reduce the operating noise of the compressor, silencer chambers, either separate from or integrated into the cylinder housing, are provided which are connected by flow channels to the admission and expulsion valve group in the cylinder head. Due to the use of cylindrical electric motors and their physical association with the compressor, such motor-compressors are comparatively wide which can be accepted in large refrigerating machines, e.g., domestic refrigerator cabinets and freezing chests. However, if the refrigerating machines have smaller dimensions, such as in camping vans or caravans, as transportable units then considerable difficulties of arrangement arise which are attributable particularly to the relatively great width of the unit. Since in the case of the above mentioned applications, the only electrical energy available is frequently that generated in the vehicle itself or by a particular unit, the energy and power consumption of such refrigerating machines with their motor and compressor in a housing is a considerably more important factor than is the case, for example, with normal mains-operated domestic refrigerator cabinets. It is therefore important that an adequately high torque is available for starting the piston compressor, because a comparatively high pressure generally acts upon the piston end and the electric motor therefore has to start under load. In order to keep the power consumption within limits in spite of this fact, it is also necessary for the energy consumption of the electric motor to be adapted to the relevant operating loads of the refrigerating machine.
The object of the invention is to produce a motor-compressor which fulfills the above-mentioned desiderata, that is one in which dimensions can be small, the electric motor of which can develop a high torque when starting, and the energy consumption of which can be adapted to the operation of a refrigerating machine.